For convenience, description is given in the following with reference to a 50 gallon metal barrel as an example.
At present, moving 50 gallon metal barrels is a job requiring manual labor. Moving 50 gallon barrels is disadvantageous and a slow operation because the barrels must be loaded onto, and off from a carrier by hand. Besides, for barrels containing poisonous substances, manual loading and unloading operations involve potential hazards to the handlers.